Geomagnetic Storm Impacts On The Ionosphere Over Türkiye During Solar Cycle 25: Focusing On The May 2024 Storm

Abstract

The interaction between solar activity and Earth's magnetosphere magnetosphere-ionosphere system often results in geomagnetic storms that disturb ionospheric electron density. In this study, we analyse the ionospheric response to selected geomagnetic storm events during the Solar Cycle 25, focusing on the mid latitude region of Earth, including Turkey. Hourly Kp and Dst indices obtained from the OMNI database are compared with global TEC maps provided by NASA CDDIS. Storm time anomalies include short term enhancements and irregularities in electron content, correlated with geomagnetic activity. Unlike equatorial regions, mid-latitude ionospheric responses exhibit distinct features such as Storm Enhanced Density (SED). These findings emphasize the importance of continuous space weather monitoring for navigation and communication systems.

Figures (10)

• Figure 1: The area analyzed in this study, covering the geographical region of Türkiye between $36^{\circ}$–$42^{\circ}$ N latitude and $26^{\circ}$–$45^{\circ}$ E longitude.
• Figure 2: Two-dimensional TEC anomaly ($\Delta \mathrm{TEC}$) maps for the pre-storm (2024-05-10 00:00 UTC), main phase (2024-05-11 03:00 UTC), and recovery phase (2024-05-12 12:00 UTC) of the geomagnetic storm. Global $\Delta \mathrm{TEC}$ distributions are shown in the upper panels, while the lower panels present a regional zoom over Türkiye (36$^\circ$--42$^\circ$ N, 26$^\circ$--45$^\circ$ E). Positive and negative anomalies indicate enhancements and depletions relative to the quiet-day TEC level, respectively. The color scale represents $\Delta \mathrm{TEC}$ values in TECU.
• Figure 3: (a) SDO/HMI intensitygram showing the Earth-facing active region NOAA AR 3664 on 10 May 2024. (b) SOHO/LASCO C3 image on 11 May 2024 capturing the Earth-directed halo CME associated with AR 3664.
• Figure 4: Temporal evolution of geomagnetic indices $Kp$ (blue) and $Dst$ (red) between 9–13 May 2024. A G5-class geomagnetic storm peaked on May 11, reaching $Kp$ = 9 and $Dst$ = -400 nT.$Dst$ is plotted as -Dst for clarity.
• Figure 5: Mid-latitude mean Total Electron Content ($TEC$) derived from Global Ionospheric Maps (GIM) between 9–14 May 2024 (DOY 130–134). A pronounced depletion is observed on 11 May, when TEC values decreased from about 50 to 15 TECU, corresponding to the main phase of the geomagnetic storm shown in Figure \ref{['fig:kp_dst']}. The recovery trend after 12 May reflects gradual ionospheric reionization during the storm’s recovery phase.